C-sharp (Musical Note)

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C-sharp (C#) is the note C raised by one semitone using a sharp (♯). On the piano, it is the first black key in each group of two black keys.

What is C-sharp?

C-sharp is an example of enharmonic equivalence. In the equal temperament tuning system, it sounds exactly the same as D-flat (Db), even though the two note names are used in different musical contexts.

C-sharp appears naturally in keys such as D major, A major, E major and C-sharp minor. The choice between C-sharp and D-flat depends on the key signature and harmonic function.

How is C-sharp used in piano playing?

C-sharp is one of the most frequently used black keys on the piano. It appears in many common scales, chords and chord progressions used in pop, rock, blues and jazz.

Learning to recognize C-sharp quickly helps piano players navigate the keyboard more confidently and understand how sharps and flats function in different keys.